I have a 2000 ford ranger with the 3.0L.
When I drive it 60 to 70 mph. It will lose speed up hill.
I check the fuel pressure it runs to 60/59 at idle. Then I hit the gas the pressure drop to 55 to 52. I'm not sure the pressure should drop or gain pressure above 60.
So I'm I right or wrong?

 

Above 50psi is fine, spec is 55psi average under load

It would have to drop down to 30psi to show Lean codes and loss of power

Clogged exhaust will cause power loss at highway speeds

3.0l Vulcan engine is a HIGH RPM engine by design
Makes best power at 3,700rpms, most engines do that at 2,700rpms
If you have an automatic you need to keep RPMs up by manually downshifting when going up a hill, need to keep RPMs above 3,200 or you will lose power

Other thing is lower compression, as an engine gets older is compression goes down, so it loses power, more noticeable under load, but that's not expected until engine is over 400k miles

 

If you have larger than factory size tires, it will do that as well if you don't change rear end gears.